Most fiber optic components, such as fiber optic couplers and wavelength demultiplexers, are fragile components and need to be protected from environmental influences and other abuses both during use and during production thereof. For example, a fiber optic coupler which is used in optical fiber interconnection arrangements to couple electromagnetic waves from one of two or more optical fibers to another optical fiber in the group may be formed by fusing and tapering two or more optical fibers together. The fabrication usually involves aligning principle axes of two or more optical fibers after removing a portion of a protective jacket on the optical fibers. They are then brought together and heated to fuse and taper the optical fibers resulting in a fused and tapered coupled region for coupling of optical power. Such couplers have been used in optical communications, optical sensors, and fiber optic gyroscopes.
Generally, fiber optic components, and in particular fiber optic couplers, are very sensitive to environmental influences because the optical material of which the optical fibers are made is very fragile. In the case of the fiber optic coupler, the coupling region is not provided with a jacket so adverse environments influence the quality of the optical material of the fiber optic coupler and/or the signals transmitted through the fiber optic coupler. Therefore, the optical signal processing performance of fiber optic components in various environments typically depends upon the type of housing or package in which the component is positioned for protection and on the method used to assemble the packaged fiber optic component.
Packaging techniques which have been used to protect fiber optic components from deleterious environmental influences include the use of a glass protective body, for example, quartz glass tubes, as a primary protective covering. Such glass tubes, in particular, provide support for the coupled region of the fiber optic coupler. The coupled region is typically placed within a central open portion of the slotted quartz glass tube and epoxy is applied at the ends of the tube to secure the optical fibers extending from the coupled region. The glass protective body has also been protected secondarily with an encapsulating compound which is extremely messy to apply, or a stainless steel tube, which requires the tedious task of sliding the often lengthy input or output fibers of a fiber optic component through the tube before the tube can be affixed or mounted on the component. This sliding operation during production often leads to damage of the fiber leads or the component itself. Securing the stainless steel tube about the glass protective body with an adhesive is also a messy, time consuming process. The excess handling required to package such fiber optic components results in degradation to the fiber optic component capabilities and may also cause latent failure of the fiber optic component inside the glass container. In addition, the stainless steel tube packaging technique is not easily utilized with different shaped glass containers, for example, a square glass container.
Marking secondary protective coverings such as stainless steel tubes with product identification information has also been difficult. For example, the stainless steel tube is round and special machinery is necessary to mark such a shaped item. In addition, when encapsulating compounds or stainless steel tube techniques are utilized to package fiber optic components, repair or testing to determine failure is also difficult. Removal of the stainless steel tube from the fiber optic component or removal of the encapsulating compound results in additional component damage, reducing the effectiveness of failure analysis.
Techniques such as those discussed above for packaging fiber optic components leave much to be desired. The protection techniques available may cause damage to the fiber optic components during packaging, increase the handling required for packaging such components, reduce the effectiveness of failure analysis, and make identification marking of such components difficult. This is particularly true with regard to fiber optic couplers. Thus, it has been observed that the packaging techniques utilized present a severe limitation to the use of such packaged fiber optic components in communication applications. Therefore, an improved package and packaging method for fiber optic components is desired.